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The treatment of solid waste in controlled composting facilities is an important possibility for reducing garbage. Natural and synthetic polymeric materials can be used for many purposes, for example, as packaging materials, where compostability is required. A prerequisite for official regulations and the decision as to which materials may be composted is investigations on their biodegradability and the quality of the compost produced. Several standardization groups at the ISO, CEN, and DIN are developing definitions, test methods, and classification systems for differentiating compostable from noncompostable materials. The concept which will be standardized and used in Germany is described in detail. It includes characterization of the test material, determination of the biodegradability using laboratory tests such as simple aquatic batch tests and a controlled aerobic composting test, investigation of the disintegration of the test material in industrial or bench-scale composting facilities, and finally, chemical and ecotoxicological analysis of the compost produced.

A laboratory method is presented for investigating the biodegradation of an organic test material in an aerobic composting system based on the evolution of carbon dioxide. In addition to carbon conversion, biodegradation can also be monitored through weight loss and physical disintegration. The test method is different from other biodegradation tests, especially aquatic tests, because of the elevated temperature representative for real composting conditions and also because of enhanced fungal degradation activities. A ring test was run using paper and poly-beta-hydroxybutyrate/valerate as test materials and cellulose powder as a reference material. The test results and the experience gained by the participants showed that the method is suitable and practicable. Experience with real technical-scale composting facilities confirms that the method provides test results of high predictive value. The test is designed to become a European Standard in connection with determining the compostability of packagings and packaging materials.

The ECETOC method for determining the anaerobic biodegradation of organic compounds was evaluated by a ring test with palmitic acid and polyethyleneglycol 400 and improved to become an International Standard. The method is based on measuring the pressure of the produced biogas and the dissolved carbon dioxide as inorganic carbon at the end of the test. The results of the ring test and a description of the method are presented.

In order to classify packaging materials as capable of organic recovery according to the packaging regulation of the European Union, the intended materials must be tested for their compostability. An important prerequisite is the determination of biodegradability by standardized test methods. Details of the intended tests are not comprehensible without further knowledge of the problems of biodegradation testing. The test methods and the limit values used to evaluate the biodegradation results are presented and discussed against the background of established test methods and limit values for chemicals. Furthermore the problem of ecotoxicity tests in connection with compost quality is discussed and an overview of European test laboratories is given.

Eighty-seven dyestuffs have been tested in short-term aerobic biodegradation tests. The results confirmed that dyestuffs are most unlikely to show any significant biodegradation in such tests. With many dyestuffs a substantial colour removal was observed which may be attributed to the elimination of the dyes by adsorption. In some cases DOC (Dissolved Organic Carbon) removal did not correlate with colour removal and this is attributed to the presence of non-coloured organic components in the dyestuff.

A programme of work was undertaken with the aim of developing a test method for the assessment of anaerobic biodegradability. A number of methods were examined and the influence of key parameters such as concentration of test compound, inoculum concentration and pretreatment, digester design and media composition were investigated. On the basis of the obtained results a test method suitable for screening chemicals for anaerobic biodegradation is recommended. The technique is simple, requires only a knowledge of the carbon content of the chemical under test, and is applicable to poorly soluble compounds. The proposed test guideline provides data of acceptable reproducibility and it is recommended that the method now be examined in more laboratories using a wider range of chemicals.